SAN BRUNO, Calif. (AP), Jun 08 - Nearly nine months after federal investigators began probing a deadly pipeline explosion near San Francisco, a California utility quietly revealed its ruptured line had sprung a leak in a nearby spot years before, a top safety official said.

National Transportation Safety Board Chair Deborah Hersman called Pacific Gas & Electric Co.'s recent disclosure of the 1988 gas leak ``troubling'' as she prepared to announce three new safety recommendations at a news conference Wednesday in San Bruno.

``If it took them months to realize they had a leak on the same line just nine miles south of the rupture site and only now we're hearing about it, that's very troubling,'' Hersman said. ``They clearly weren't contemplating this information when they were assessing the risk on this line.''

Learning about past problems so long after the investigation began hampers federal investigators' ability to quickly determine what caused the fatal blast, she said. Hersman added that the recent disclosure shows that PG&E's record-keeping is inadequate.

Company spokeswoman Brittany Chord did not immediately respond to an email Wednesday seeking comment.

The board is still probing what caused the Sept. 9 explosion, which sparked a gigantic fireball that engulfed a San Bruno neighborhood and killed eight, injured dozens and destroyed 38 homes.

Hersman said one of the recommendations will press the company to set up new procedures so emergency responders are immediately and directly notified when a possible pipeline rupture occurs.

She also planned to ask the Pipeline and Hazardous Materials Safety Administration, which enforces federal rules for the safe operation of interstate pipelines, to urge pipeline operators nationwide to improve emergency communications plans and share more information about their systems with first responders in local communities.

Hersman is touring the San Bruno neighborhood torched in the blast and is meeting with families who lost relatives in the explosion. She also will meet with local officials and PG&E executives.